A resonant switching power supply controls a current or a voltage into a sine wave, and performs switching with either the current or the voltage almost equal zero. This helps dramatically reduce switching loss and noise.
In particular, a serial resonant switching power supply, being a current-voltage resonant circuit, not only helps reduce switching loss but also operates with a smaller surge in the circuit and achieves higher efficiency compared with other circuit designs such as a phase-shift full-bridge design. Because of these benefits, serial resonant switching power supplies have been introduced in many appliances like as power supplies in liquid crystal television sets and servers.